Porous carbons are useful materials for a wide range of applications like catalysis, purifications, fuel cell electrodes, and gas storage. The development of porous carbons as catalyst supports for fuel cell electrodes is of current interest for vehicle propulsion applications.
Porous carbons may have pores that vary over a range of pore sizes and these pore sizes have been categorized or classified. Pore sizes uniformly, in the size range of two to fifty nanometers in opening size, are called mesopores and carbon particles with mesopores are favored for fuel cell electrode applications. Smaller pore sizes, less than about two nanometers are termed micropores. Such pore sizes are usually too small for fuel cell catalyst support applications. Larger pore sizes, greater than about fifty nanometers, are termed macropores. Macropore size support particles are typically too large for fuel cell catalyst applications.
The most commonly used porous carbon materials are activated carbons, which are often produced through a physical or chemical activation process that produces microporosity. Activated carbons are typically microporous (pore diameter<2 nm) and contain widely distributed micro-, meso- and macro-pores. They often contain high surface areas ranging from 800 to 1500 m2/g. The small-sized micropores, however, may limit their applications where rapid mass transport or larger pore sizes are required. In order to overcome the limitations, there has been a great deal of interest in the synthesis of mesoporous carbon, a class of porous carbons with attractive characteristics, such as larger pore size, narrow pore-size distribution, high surface area, large pore volume and highly ordered framework structure.
This invention provides a method of making carbon particles with mesopores.